The "little elf" in the picture is called Ye Yang, a name that may sound strange, but it has captured people's hearts.
"It's so adorable. The first time I saw it, I thought it was very small, but it's exquisitely beautiful, just like a little lamb in a cartoon."
Ever since he first encountered the leaf sheep, diver Alarhuán has been captivated by this creature, even referring to it as the "Shaun the Sheep of the sea."
In fact, its name is quite misleading.
The leaf sheep, neither a plant nor a sheep, is actually a type of sea slug that lives in shallow waters.
It is very small, measuring only about 5 millimeters long. As it matures, its transparent body turns green, with a soft and fluffy texture. It has a pair of small eyes on its face, along with black tentacles, and a hint of blush on its cheeks, resembling a little lamb.
Hence, people refer to it as the leaf sheep.
The leaf sheep, like their terrestrial counterparts, also eat grass, but they feed on algae.
In this aspect, the leaf sheep share similarities with the mythical creature, the chimera, as they consume almost any type of algae, some of which they can't digest.
After ingesting algae, the leaf sheep collect and retain the chloroplasts from the algae in their cells. These assimilated chloroplasts can provide energy to the leaf sheep through photosynthesis.
In a way, the leaf sheep can be considered a mixotrophic organism, engaging in both autotrophic and heterotrophic nutrition simultaneously.
However, the photosynthetic ability of the leaf sheep is relatively primitive, and they cannot rely solely on photosynthesis to sustain their lives.
The underage paramecium is transparent.
Its relationship with chloroplasts is like an employer-employee relationship.
It hires chloroplasts to create energy for the body, but it also needs to pay these "employees," so it has to consume some algae to obtain proteins and energy to provide to the chloroplasts.
In other words, it cannot survive solely on photosynthesis by chloroplasts without eating or drinking; it also needs to feed itself.
The green sea slug
Compared to others, the green sea slug is more advanced.
The green sea slug can also incorporate chloroplasts from food and use them. Once it has absorbed enough chloroplasts, it signifies maturity as its color changes from reddish-brown to bright green.
At this point, the energy produced by the chloroplasts' photosynthesis within the green sea slug's body is sufficient to sustain its daily needs.
The green dot is the chloroplast.
Therefore, as a green sea slug in its youth feeds on algae, as an adult, it can survive for 9-10 months solely through photosynthesis without eating or drinking when food is scarce (with a lifespan of only 1 year).
Furthermore, the green sea slug, through its symbiotic relationship with the chloroplasts, merges the genes of the consumed algae with its own genes, passing them on to the next generation.
This process enhances the cooperation between the green sea slug and the chloroplasts, making it more profound and perfect.
If the chloroplasts get damaged during their use, the green sea slug has the ability to repair them. Even without food or energy supply, the chloroplasts within the green sea slug remain stable and continue functioning.
These mechanisms differ from those of hybrid sheep.
The leaf sheep and its eggs
In the end
Overall, when it comes to working with chloroplasts, the leaf sheep and the sea slugs with green leaves have different natures.
While the leaf sheep undergo photosynthesis, they also need to feed themselves to supply the chloroplasts, much like a boss and an employee: you help me work, I pay you a salary, mutually beneficial.
On the other hand, the sea slugs with green leaves can fully rely on photosynthesis for survival. Their relationship is more like that of a boss and a shareholder: even without feeding in return, the chloroplasts still provide energy for the entire organism.
During development, the sea slugs with green leaves are quite selective in choosing their chloroplasts, only incorporating chloroplasts from a specific type of algae.
Once the whole system is established, they no longer have to worry about eating. They can have a bite of seaweed if they feel like it, or simply leave the energy issue to the chloroplasts if they don't feel like eating.
